The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
Robot-camera calibration accuracy is essential for effective use of visual sensor-guided robotic platforms. Known methods for robot-camera calibration include determining extrinsic characteristics that describe a relative position and orientation of the camera with regard to a coordinate system of interest. Known calibration methods rely on human supervision to manually provide corresponding points in a camera's reference frame by inspecting images from the camera and marking a location of a robot end effector or some other fiducial marker. This method may be accurate and suitable for a one-time calibration, but can prove tedious for a flexible manufacturing environment where calibration needs to be performed frequently. Other known methods find the corresponding points by using computer vision and employing special calibration objects, calibration patterns, or other fiducials placed in the robot's workspace or attached to the end effector. Such calibration objects can include, e.g., a checkerboard pattern or an LED. Use of a calibration pattern can be problematic in that they may not be suitable for a particular work environment, may disrupt normal operating conditions, and may require position and pattern calibrations, thus increasing the quantity of correspondences and the complexity of the optimization.